1216064557 has 4 divisors (see below), whose sum is σ = 1216168416. Its totient is φ = 1215960700.

The previous prime is 1216064527. The next prime is 1216064611. The reversal of 1216064557 is 7554606121.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1216064557 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1216064527) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31753 + ... + 58654.

It is an arithmetic number, because the mean of its divisors is an integer number (304042104).

Almost surely, 2^1216064557 is an apocalyptic number.

It is an amenable number.

1216064557 is a deficient number, since it is larger than the sum of its proper divisors (103859).

1216064557 is an equidigital number, since it uses as much as digits as its factorization.

1216064557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 103858.

The product of its (nonzero) digits is 50400, while the sum is 37.

The square root of 1216064557 is about 34872.1171855108. The cubic root of 1216064557 is about 1067.3795477516.

The spelling of 1216064557 in words is "one billion, two hundred sixteen million, sixty-four thousand, five hundred fifty-seven".